Process of obtaining sulfur from smelter-gases.



H. SANBORN, H. G. MGMAHON, J. T. OVERBURY & S. W. YOUNG. PROCESS OF OBTAINING SULFUR FROM SMELTER GASES.

' APPLICATION FILED JULY26,1911. 1,062, 1 20, Patented May 20, 1913.

llllll STATES PATENTOFFIOE.

HAMILTON may, HENRY can IQIA HON, IOU 'IBUIBULL ovna- BUBY, OF SAN FRANCISCO, AND STEWART WOODFORDYOUIG, 01' PAID ALTO, CALL I'OBNIA, ASSIGHOBS, BY DIRECT AND mu: ASSIGNIEIITS, l0 THE THIOGBN COIPANY, 0! SAN mNCISCO, CALIII'OBIIA, A CORPOBL'I'IOH OI racemes-or onrnme scam no! sienna-ours.

citizens of the United States, have invente a new and useful' Process of Obtaining Sulfur from Smelter-Gases, of which the following is a specifica tion.

Our invention consists in a process for abating the sulfurous fumes arising from the operation of smelters, and for recoverin the.

by-products of such va ors or gases an for the recovery of sulfur rom any and all sulfur containing substances.

In the process of smelting ores enormous quantities of sulfur are released in the form of sulfur dioxid, which appears as a gas. This gas when resent in the atmosphere in any considerabl uantities acts as a poison to vegetation an has deleterious efiects u on man and animals. The ridding smelter gases of their su fur dioxid has become ave serious one, a large number of smelters ing at the present time restrained from operation by injunctions granted by the courts in order to protect the a ricultural interests in the neighborhood. Tie amount of sulfur dioxid-set free in the roasting of an ore is approximately twice the weight of the sulfur contained inthe ore, and as ores frequently run to above of sulfur and some kinds of ores generally contain about 10%, it will be readilv seen that the amount of the gas released om a smelter working one thousand tonsnof ore a day will be from 200to 500 tons, equivalent to from l0O-to 250 tons of sulfur.

We have carried on a seriesof experiments for the purpose of devising a practicalmethod whereby the troubles caused by the presence of this gas can be abated, and whereby the large quantities of sulfur going to waste at the resent time may be recovered and used 1n the arts and industries where they are in large demand.

The method which we have devised and resent invention depends upon a chain of chemical operations whereby the aboveresults are accomplished in a commercially practicable manner.

' lpeozllcation or Letters Patent.

Application new; 26, i911. Serial 19,640,571.

rnia, and S'rnwan'r roblem of' PatentedMay 20,1913.

The essential op erations are as follows: First, .the gases are submitted to the actlon of asuitable sulfid, (such as a sulfid of calcium, magnesium, sodium, or a metallic sulfid such as iron, or a non-metallic sulfid,

such'as carbon bisulfid'). By this means the sulfur dioxid is absorbed and when an alkalme sulfid'is used for instance, the result-in product consists of a mixture of sulfur an the sulfite and sulfate of the alkaline base used; (together with small quantities of co plex sulfur compounds) the sulfate be- .ing formed as the result of oxidation occurfrom this product by fusion, solution, distillation or other suitable method. The residue then consists mainly 'of a mixture of su to and sulfate of the base used.

hi -rd, this residue is next treated with ca naceous materials at high temperature, or by some other process which brings about thl Seduction of the sulfite and sulfate 'to su Fourth, the sulfid thus obtained is again used for the further absorption of sulfur dioxid and other substances as in step one; the cycle thus beingrepeated.

In practice, we prefer to use calcium sulfid because of its chea' mess and its qualities as an active agent or this purpose. In actually starting operations, we use ordinary lime, or lime stone, which when it has become saturated with :the sulfur dioxid and trioxid consists of a mixture of calcium sulfite and sulfate. This is then reduced to calcium sulfid by the above specified means. In the first operation there is thus no sulfur recovery.

In all subsequent operations where the absorption is accomplished by the plant for the operation of the met od.

A represents a suitable supply tank or reservoir adapted to contain the active agent of our process, preferably, as before stated,

'through a pipe 12, for re-treatment.

sulfid of calcium. From this container A the sulfid is dro ped or sprayed in suitable form through time absorption chamber or tower 2; the active a out being delivered thereinto from the pergorated pipe 3. lhe sulfurous gases or fumes are delivered from the smelter or furnace 'into the tower 2 through the due a so that in ascending through the tower 2 they are brou ht into intimate contact with the finely divi ed particles or spray of the absorptive material. in this upward traverse of the tower by the gases enter-in at 4 the sulfur dioxid and the sulfur trioxid are absorbed, and the saturated material, in the form of a mixture of calcium sulfite and sulfate, falls to the bottom of the tower and accumulates there as a sludge, indicated at 5. The fumes which pass out of the tower at 6 are free from sulfur dioxid or sulfur trioxid and may be allowed to escape to the outer atmosphere 'or may be subjected to a further treatment for the recovery of any by-products carried over.

From the trap 5 the recipitated sludge and solids are delivered t rough a conduit 7 by suitable means, as a pump 8, to a settling tank 9. Subsequently, the solids from this tank 9 may be treated in a regenerating furnace 10. Here they are first dried with a low heat. The temperature is then raised to such a degree that the sulfur is distilled off and collects in a condensing chamber 11. Any uncondensed gases remaining in chamber 11 are re-delivered back into the flue 4 The residues from the sulfur distillation in furnace 10 are then covered or mixed with coke, coal, or other reducing materials fed in through a hopper 13, and the temperature By the term spray, either in this appli-v cation orin the claims, is meant, an atmosphere charged with an active a cut, either in the form of a liquid ora pow er.

Having thus described our invention, what we claim and desire to secure by Letters Patent is 1. A continuous or cyclical process for treating the sulfurous fumes arising from the smelting of ores and the like, which con sists in passing these fumes into intimate association with a suitable sulfid to absorb the sulfur dioxid, collectin the solid particles resulting from such asorption, separating the free sulfur from said solids, 'sub jecting the residue to the action of neat and carbon to regenerate the sulfid and reusing the regenerated sulfid in the continued cycles of operation.

. 2. A continuous or c clical process for treating the sulfurous umes arising from the smelting of ores and the like, which consists in passin these fumes into intimate association-wit a suitable sulfid to absorb the sulfur dioxid, collecting the solid particles resulting from such absorption, separating the free sulfur from said solids, subjecting the residue to the action of heat and carbon to regenerate the sulfid and re-using the regenerated sulfid in the continued cycles of operation, usinglime or limestone as the initial active agent, the first cycle roducing calcium sulfid for use in the su sequent cycles of operation.

In testimony whereof we have hereunto set our hands in the presence of two subscribing witnesses.

HAMILTON SANBORN.

HENRY GRATTAN MGMAHON, JOHN TRUMBULL OVERBUBY. STEWART WOODFORD YOUNG.

Witnesses:

JOHN H. HERRING, CHARLES EDELMAN. 

